# Questions tagged [torque]

For questions about torque as it relates to electronics. Consider using in conjunction with related tags such as "motor" (and more specific motor-related tags), if applicable.

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### Torque Motor. Need advice for pole count and windings

I taught myself the basics of motor design and am about to build a torque motor with 20 Nm constant torque and 500 RPM, BLDC 48-72 V, hollow shaft 105 mm, 60 mm length. I saw several images of torque ...
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1 vote
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### Motor peak and continuous torque calculation

Given these motor characteristics for a BLDC motor ( maximum speed = 2000 RPM), what is the achievable continuous and peak torque with 24V input at very low RPMs (<50 RPM)?
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### Scaling up a Motor

If I take a DDR motor (Direct Drive motor like a washing machine 3 phase DC motor) and make a larger version of it so the diameter is 2x and the magnets and coils are correspondingly wider for the ...
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### Induction motors torque measurement

I am to calculate the running efficiency of a 3-Ph squirrel cage induction motor. I have the rated data for the motor. I have the load speed of the motor but I need output torque to calculate the ...
38 views

### Motor and Controller to spin Camera Array

I am in over my depth with respect to motors and drive hardware. Problem The motion control solutions I have tried have failed due to torque insufficiency and noise. Seeking I am seeking motion ...
52 views

### Do eddy currents in a rotor core of an induction motor create torque proportional to the coil current of a squirrel cage?

In a rotor of an induction motor, the core plates and wire coil conductors have non-zero thicknesses. Therefore, eddy currents non-zero too. And they approximately proportional to the coil current of ...
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### What's the difference between a direct drive/torque motor and a stepper?

A torque motor is 'either a rolled-up linear motor or a classic servo drive with a large number of poles'. As I understand it they are ironless 3 phase supply motors, though perhaps neither of these ...
149 views

### Is motor size an important factor in output performance or torque by keeping the same consumed power and voltage?

I have a problem comparing two sample motor's performance metrics . Two motors with same wattage ang voltage but different size. Big bulky motor Example: Bosch 1250 W Size Ref #1 1380 W Size Ref #2 ...
74 views

### Is power low for a high speed fan?

Got a question for my lab telling that the power consumed is low at higher speeds, why is it so? couldn't find any source backing up this statement too I did find this graph of torque vs speed, so I ...
1 vote
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### Does "Torque control" using FOC consider input (battery) voltage drop?

All information related to Torque Control using FOC technique consider a current control, so they suppose a correlation between req_Id (Id desired) and requested mechanical torque. PI regulators ...
1 vote
110 views

### How do I find the torque of a simple electrical motor?

I created a simple electric motor following Khan Academy's tutorial, and now I am trying to figure out how I can find the torque from it (which should be quite small). Here is an image of the setup ...
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I need to test several BLDC motors and their ESCs, primarily to determine the motor's capability and power consumption, as well as the ESC's ability to drive the motor at higher current. Aside from ...
340 views

### How to find the back-EMF constant of BLDC motor from a motor technical data?

I have a BLDC motor with these info (please don't pay attention to the striped column): How from these info, how can I get the Back-emf constant ? Is it just 36V/4krpm = 9 V/krpm ? Thank you a lot.
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### Correct understanding of torque constant for BLDC using FOC

I have a BLDC motor with sinusoidal windings that I drive with FOC technique. With my recent knowledge earned by implementating FOC, I got confused with the typical motor constant given in ...
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### Maximum torque conditions

Suppose the following machinery : The induced torque is given by the following formula : where K is a constant which depends on the motor construction. Bs is the constant (in magnitude and in ...
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### Torque in kg·cm vs N·cm (servo vs rotary switch)

I don't understand the different specifications of the maximum force of a servo motor vs the torque of a rotary switch. In the following example, there is a servo spec'ed at "Maximum Torque at 6V:...
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### Torque control of a BLDC motor

Please forgive my lack of perfect electronics knowledge. I am here to learn. I understand I am clearly missing and misunderstanding something important. The aim of this question is to find out what it ...
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### Designing a unipolar stepper driver using STM32 MCU, lack of torque

I am working on my first robotics project which will hopefully become a desktop sized KUKA iiwa. Unfortunately, I have only just completed the first year of my electrical engineering degree so have ...
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### What is rotor torque in the stepping motor context?

I have the following datasheet for a stepping motor. I am wondering what "Rotor Torque" means in the stepping motor context. My first guess would be the torque produced by the rotor under ...
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### Calculating the torque and RPM requirements for a DC motor

Say I'd like to calculate the motor specs required for lifting a 1kg weight at a rate of 1 m/s. How much torque and RPM should the motor have, assuming a wheel radius of 1cm? My calculations are as ...
263 views

### How do I calculate the RPM and torque of a 12 V DC motor that gets 5 V?

I have a PCB that outputs 5 V to each of the two motors. It was part of a robotics kit that included two 12 V 360 RPM motors. I want to attach a 12 V DC motor with 3500 RPM. How do I calculate how ...
1 vote
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I work with compressors and usually the starting characteristic for fixed speed machines with starters is that the machine starts unloaded (star starter), after that the compressor unit is loaded and ...
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### Can you design a DC motor with any arbitrary torque speed curve?

Title pretty much says it all. I have a low-rpm (30-160) and moderate-torque (2 N-m) application. These characteristics are pretty easy to hit with an off-the-shelf dc motor + gearbox. But let's say I ...
1 vote
138 views

### Can not get maximum torque (stall torque) when current reach peak current

I am using FOC to control torque of 220V AC servo (SPMSM) with 36V power supply at low speed (100-200rpm). I tested with some servos (different manufacturers) which has specs as the below table. But I ...
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1 vote
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### Will running four motors (two high speed and two high torque) get the robot rolling? [closed]

I've been building a 2WD robot for 3 months now and been switching the motors frequently and been running into the same issue - low torque. I had these low RPM, high torque motors around and thought: ...
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### VFD Driving a 40HP Inverter Rated Motor showing high Torque, Output Current at Low Speed

I am having some difficulty troubleshooting a Toshiba VFAS3-4300PC. I am using it to run a 40HP inverter rated motor that is driving a VRU Screw Compressor. I have the frequency range set for 12-60Hz. ...
54 views

### BLDC torque and speed control

Actually I drive a DC motor in speed and torque at the same time. I would like to know if there is a solution to do the same with a BLDC. The motor is 50W max. I can make a custom PCB to use a BLDC ...
1 vote
239 views

### Achieving zero torque from DC motor

The current project I am working on requires a motor to provide ~2 Nm to a spinning shaft and then upon command provide ~0 Nm, hence acting like a bearing. The motor will have an attached encoder, and ...
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### How can I connect two motors in parallel with different RPM and voltage?

I have a kid's electric toy car with a 12 V battery and 2 DC motors (Model: RS380/6 V & 12 V with 15000 RPM) connected to battery in parallel and to wheels using gearboxes. For some reason, the 6 ...
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1 vote
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### Reverse engineering a torque sensor

I am trying to reverse engineer a torque sensor. I have found the two data lines that are providing the torque value output to the ECU. Here are the waveforms that I have captured that show max. ...
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### Torque to FOC Iq current conversion

I am controlling the quadrature current (Iq) of this BLDC using the TMC4671 FOC controller. The FOC control seems to work fine, but the end goal is to control the real torque produced by the motor. I ...
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### DC motor efficiency

I would like to build a Moment of Inertia machine: A machine that rotates an object (with a DC motor) and can also record the angular velocity and use this to find the moment of inertia. Initially I ...
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### Need help figuring out how to organise a system to run a stepper motor at low speed without Steps-skipping

TL;DR : How to prevent step-skipping with a NEMA gearbox motor at low speed. Edit: following @glen_geek comment, removing the load on the system seems to remove the problem, hinting at inertia and ...
37 views

### How much lower than the ideal torqe curve is the actual torque of a PMSM running at overspeed?

VFD-controlled PMSM's are said to produce constant maximum torque up to the rated speed. Above the rated speed the VFD performs defluxing and produces constant power. This should then mean that at 200%...
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### Is there a large difference between full-step and half-step stepper motors' torque at very low speeds?

I'm using a NEMA 23 for a solar tracker, which means my mechanism will move a single step every 5~10 minutes, and the step angle is 1.8 degrees which I need to bring down to 0.01 degrees. Now I need ...
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### DC motor spins faster in reverse

Due to certain circumstances I need to run my brushed DC motor in reverse (positive to black wire, negative to red wire). What I noticed is that when set up this way running at no load requires 1.5A. ...
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### Can a BLDC motor still provide max torque for holding position when I run it at 24 V instead of 48 V?

I would like to do a Leg Robot project. I have an AK80-64 BLDC motor from T-motor. The specification says it can be operated at 24 and 48 V. Can the BLDC motor still provide max. torque for holding ...
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### Why does this DC motor increase in current and then decrease as the speed increases?

Well, the general answer to this is that as the motor needs to overcome the inertia from its state of rest, it requires high starting torque and aka high current is consumed to do that work. On the ...
2k views

### How to calculate torque of a three-phase induction motor?

I have a three-phase induction machine with following nameplate data: $V_{s_n}=\frac{425}{\sqrt{3}}\,\mathrm{V}$ - effective value of the phase voltage, $f_n=70\,\mathrm{Hz}$ - nominal frequency, \...
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### Using a BLDC for variable counter-torque

I have a project in mind where rather than using weights for resistance in exercise training, I would use a BLDC for resistance. I want to have a pulley system hooked up to a BLDC, similar to the ...
1 vote
123 views

### DC Motor Time to Attain Full Speed Formula Origin

There is no formal discussion but I see a formula that relates the average available torque to moment of inertia in problems from Electrical Technology by Theraja. I have tried searching about this ...
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### Transfer function of two frequency spectra

When you have two amplitude frequency spectra (fourier spectrum), in this case of a torque ripple, how do you define the transfer function (or the ratio) between both? How do you "divide" ...
1 vote
2k views

### Why does higher voltage produce better torque from stepper motors?

I'm working with stepper motors and I have a question. I have found that if I use a higher voltage switching source, I get better torques from the motor. Why is this?
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### Can you use a DC brushless motor as a torque motor?

I've got an outrunner brushless DC motor (Flipsky 63100 190KV 5500W if that's relevant). It'll be used to spin normally sometimes, but I also need it at other times to give resistance to motion. ...
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### Choosing a motor

Long time listener, first time caller etc! Also, if you think this could be better answered somewhere else please let me know. I'm building a pottery wheel at the moment and I'm in a bit of a quandary ...
447 views

### Some doubts regarding electronic throttle motor

I am trying to wrap my head around the working of electronic throttle bodies. So they usually have a brushed Permanent Magnet DC Motor which actuates the throttle plate (butterfly valve) via a gear ...
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### Electrical torque and electrical power of a generator?

Having the electrical torque and the angular speed of a synchronous generator, can I calculate its electrical power output as the product between the electrical torque and its angular speed w (Pe=Tew) ...
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### Fundamental understanding of motor torque

I have the following elementary question regarding motors: Motors provide mechanical torque as output. Every motor has a particular torque-speed characteristic curve which tells us how much torque the ...
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